Question: Simplify the following expression: $z = \dfrac{k^2 - 17k + 70}{k - 7} $
Answer: First factor the polynomial in the numerator. $ k^2 - 17k + 70 = (k - 7)(k - 10) $ So we can rewrite the expression as: $z = \dfrac{(k - 7)(k - 10)}{k - 7} $ We can divide the numerator and denominator by $(k - 7)$ on condition that $k \neq 7$ Therefore $z = k - 10; k \neq 7$